5

Why Sex?

Genetic variability
as a reason for sexual reproduction. Sexual selection and peacocks'
tails. Lessons from chimpanzees and bonobos. Evolutionary psychology
on the role of sex in brain evolution.

A. Why Sex?

A male peacock struts
in front of the camera. "Peahens only mate with well-endowed
males," the narrator says. "No fancy display? No sex.
No passing of genes to the next generation. That's something every
living thing is programmed to do."

The scene shifts to fighting
baboons, and the narrator continues: "It's worth fighting for,
maybe even dying for. In fact, from an evolutionary perspective,
sex is more important than life itself." We watch salmon spawning
and dying, then a human family appears. "While we won't trade
our lives for sex, most of us will risk death to protect our children,
the carriers of our genes. Evolution is a story written over countless
generations. To inherit and pass on genes is to be part of that
story."

We meet Rutgers University
evolutionary geneticist Robert C. Vrijenhoek, who tells us: "That's
our immortality. That's what connects us to humans on into the future.
That's what's connected us to all of our ancestors in the past.
That's what connects us to the ancestors that were fish, the ancestors
that were protozoans, and the ancestors that were bacteria. It's
the single thread that connects all of life on this planet."

In southwest Texas, a
research crew is rounding up parthenogenetic lizards--a species
that consists entirely of females, and does not require males to
reproduce. The crew leader says: "Some people think they actually
have to have some kind of lesbian behavior where a female mounts
a female to get the eggs to develop." We watch as one lizard
performs erotic movements on top of another. "That hasn't been
really proven yet, but it's an interesting hypothesis." The
existence of this all-female species, however, raises a fundamental
question: "Why is there sex? I mean, are males really necessary?"

Accompanied by some old
movie footage and some wildlife photography, the narrator explains
the supposed disadvantages of relying on males to help pass on genes,
but notes that almost every life on the planet is nevertheless a
result of sexual reproduction. The scene shifts to a husband and
wife and their adopted baby, and the narrator concludes: "So
males must play a critical role, and sex must offer an advantage.
Whatever it is, it's buried deep within us."

We are told that the
"biological imperative, as we all know, is to pass on genes."
Since sexual reproduction is so common, "there has to be some
fundamental biological, evolutionary reason for sexual reproduction.
This has been one of the major questions in biology for a very long
time."

The emphasis on sex in
these opening scenes is striking. Sex is more important than life
itself. Sex is our immortality. Even the story of parthenogenetic
lizards--for whom sex is irrelevant--is illustrated with a lesbian
sex scene. This episode is sure to be an attention-getter. But how
much of it will it be science?

B. The Biological Reason
for Sex

We accompany Vrijenhoek
as he conducts research on minnows that inhabit small streams in
Sonora, Mexico. The narrator explains that he "hopes to find
clues to the enduring mystery--Why sex?"--by studying a species
of fish that includes both sexual and asexual reproducers. According
to Vrijenhoek, the sexually reproducing fish are more resistant
to infestation with parasites. His hypothesis is that this is due
to the greater genetic variability that comes from exchanging genes
with other members of the population. Sexual reproduction, he believes,
leads to new combinations of genes that confer protection against
parasites.

"Here was a solution
to the mystery of sex," the narrator says. "It's the best
defense against rapidly evolving enemies. Or so it seemed, until
a bad drought dried up the pools, killing the minnows and throwing
everything into question." After the minnows returned, the
parasites were decimating the sexual fish, and the asexual ones
were doing quite well. But an experiment convinced Vrijenhoek that
this was only because the drought had led to inbreeding among the
few survivors, and had thus reduced the genetic variability of the
sexual population. He concludes that his hypothesis remains intact,
and that the principal benefit of sexual reproduction is that it
increases genetic variability.

"That's what sex
does," Vrijenhoek says. "Sex generates variability among
offspring. And when you take that away from a sexual reproducer
by inbreeding them, cloning them, you've lost the very benefit of
sex. It's that generation of an immense amount of diversity, that
diversity of your offspring, that provides challenges to everything
around it: challenges to the parasites, challenges to the viruses,
challenges to your competitors. That's the beauty of the sexual
process--[it] is the variation and wonderful diversity it creates."

As we watch human families
and children, the narrator repeats the point: "Sex generates
variation, which improves a species' chances of survival in a world
dominated by relentless competition." The scene shifts to a
men's basketball game. "For all their down side, males are
worth the trouble. Think of them as a female's insurance policy
against losing her children to rapidly evolving threats like measles
and the flu."

A viewer who knows nothing
else about this topic would probably conclude at this point that
scientists now know the answer to the question, "Why sex?"
But the viewer would be mistaken--misled by an extraordinarily shallow
and lopsided account of one of the most controversial topics in
evolutionary biology.

The very existence of
sexual reproduction presents a problem for Darwin's theory. The
easiest way for an organism to reproduce is simply to divide asexually--to
make a copy of itself. Bacteria are very successful at this. An
organism that reproduces sexually, however, must divert precious
energy into making sperm or egg cells; in the process, gene combinations
that were quite useful beforehand are sometimes destroyed through
"recombination." Then the organism must find a member
of the opposite sex and mate with it successfully. From an evolutionary
perspective, sex incurs considerable costs that must be offset by
advantages to the organism. But what are those advantages?

Various theories have
been proposed--including the genetic variability theory to which
Vrijenhoek subscribes. But situations such as the one he studied
are relatively rare; so why is sexual reproduction so widespread?

A comprehensive review
of this topic in 1988 concluded: "While there might well be
agreement about the importance of the problem of the evolution of
sex, there is no consensus about where its solution lies."
Ten years later, in September 1998, the journal Science devoted
a special issue to the evolution of sex, and said essentially the
same thing: Biologists "haven't solved the mystery of sex yet,"
partly because of "extremely lousy experimental data."
And this was after Vrijenhoek had done
his research on Mexican minnows. So evolutionary biologists continue
to "scrounge for data to support one or the other of the warring
theories of sex." According to Science: "How sex began
and why it thrived remain a mystery."See
. For a review of the research on Mexican minnows, see Robert C.
Vrijenhoek, "Animal Clones and Diversity," BioScience
(August, 1998), at:

For people who think
biology is boring, the lively debate over the biological reasons
for sex could make the field much more interesting. But people won't
learn anything about this controversy from Evolution.

C. The Origin of Sex
and Gender Differences

The narrator continues:
"If the reason for sex is a bit less mysterious these days,
its origins remain much more speculative." A whimsical cartoon
animation fills the screen. "Some believe it all got started
billions of years ago, with two single-celled creatures sharing
a chance encounter in the primordial night. They meet, and genes
are exchanged. That's what sex is all about. The moment is brief,
but it leaves them a little bit stronger, a little more likely to
survive and reproduce. Males and females came later, when random
change produced a creature that was small and fast, which turned
out to be an evolutionary advantage. Organisms with reproductive
cells like that are called males. Their goal is to find organisms
with a different specialty--providing the nutrients life requires.
They're called females. These early pioneers evolved in time into
sperm and eggs."

The difference between
sperm and eggs is then extrapolated into an account of the differences
between male and female sexual attitudes. "Males produce sperm
by the millions, with so many potential offspring it doesn't pay
to be fussy about eggs. A better strategy is to try to fertilize
every egg you can. Eggs are more complex than sperm and take a larger
investment of energy. Females make only a limited number of them.
Fewer eggs mean fewer chances to pass on genes, and that means females--unlike
males--do better if they're choosy. At a deep biological level,
males and females want different things, regardless of how things
appear on the surface."

The camera pans over
a man and woman--apparently naked beneath a sheet that is pulled
back to expose as much flesh as network policy permits--who are
engaging in sexual foreplay. "Small sperm versus large eggs,"
the narrator continues. "Quantity versus quality. These are
the evolutionary roots of the war between the sexes." This
war "can explain a lot about how species evolve, and why they
look and act the way they do. Charles Darwin was the first to recognize
the evolutionary significance of sex." These statements are
graphically illustrated with scenes of various animals engaging
in sexual intercourse.

According to the narrator,
Darwin's theory of natural selection could explain why "any
trait that improves an individual's chances of survival should spread
through the entire population. But it offered no help in explaining
the wild extravagances found throughout nature, like the peacock's
tail."

"It is hard to see
a peacock's tail as something other than an impediment to his survival,"
the narrator says. "Theologians of [Darwin's] day argued that
God created ornate flowers and feathers to inspire man's wondering
devotion. Darwin was convinced there had to be an evolutionary explanation--just
as there had to be an evolutionary explanation for why so many of
nature's ornaments are seen only on males."

To solve the problem,
Darwin formulated his theory of sexual selection, which psychologist
Geoffrey F. Miller calls "Darwin's most ingenious idea."
According to Miller, "these ornaments are not for our good.
They're to advertise each individual's fitness, its goodness as
a mate, to the opposite sex."

We watch scenes of male
animals fighting, and a movie scene of John Travolta putting on
seductive clothing, as the narrator tells us that females engage
in choice, while males engage in competition. Male competition may
take the form of fighting, we are told, or it may take "the
path of the peacock--seduction through sexual display. This is where
female choice comes in."

Commentators take turns
emphasizing that the idea of female choice was controversial in
Victorian England. Only a century later was this aspect of Darwin's
theory tested in peacocks, when experiments showed that males with
bigger, flashier tails tend to attract more mates and to have longer-surviving
offspring. "It's all a logical consequence," the narrator
says, "of the differing reproductive strategies of males, who
have lots of sperm, and females, who have fewer eggs."

As the narrator acknowledges,
however, all of this is speculation. Science is supposed to rest
on evidence, but a whimsical cartoon animation about the evolutionary
origin of sex is not evidence. In fact, most of what we have just
seen is what evolutionary biologist Stephen Jay Gould would call
a "just-so story." About a hundred years ago, Rudyard
Kipling wrote a children's book by that name which recounted entertaining
but scientifically meaningless stories about how leopards got their
spots, and other things. In just-so stories, according to Gould,
"virtuosity in invention replaces testability as the criterion
for acceptance." Evolution is telling us just-so stories, yet
we are expected to regard them as scientific and to draw two far-reaching
conclusions: First, that sex originated in "random change;"
and second, that men and women behave as they do because the former
have lots of small, fast sperm and the latter have a few large,
complex eggs.See
. The Stephen Jay Gould quotation is from "Sociobiology: the
art of storytelling," New Scientist (November 16, 1978), 530.

Not only does Evolution
rely on just-so stories, but it also frames yet another scientific
issue in religious terms. We have just been presented with two competing
ideas: the idea that "God created ornate flowers and feathers
to inspire man's wondering devotion," and the idea that peacocks'
tails are a result of Darwinian sexual selection. Then we are told
that the tendency of male peacocks with big, ornate tails to attract
more mates and have longer-surviving offspring is "a logical
consequence of the differing reproductive strategies" of males
and females--as though that somehow refutes the idea that God created
ornate flowers and feathers. Why not just present the evidence,
and leave religion out of it? Once again, Evolution goes out of
its way to speak to the religious realm.

C. Marriage and Family

"But the goal isn't
just to have offspring," the narrator continues. "The
young have to survive long enough to have their own offspring. Sometimes
that requires paying as much attention to behavioral traits as to
physical ones." In a scene from an old movie, Katherine Hepburn
has difficulty choosing between sexiness and dependability in her
man. This "mirrors a deep biological dilemma," the narrator
tells us. "For some species, the chances of offspring surviving
increase if a female chooses a mate who'll stick around over the
one with the best genes."

We watch songbirds in
which males and females share the job of parenting. The narrator
tells us that the female needs the male's help, but the male will
stay home only if he believes the chicks he's helping to raise are
his own. "The result is monogamy--a social solution to a biological
dilemma." The scene shifts to the human family we met earlier.
The husband and wife affirm their commitment to their adopted child
and to each other as the narrator says that "monogamy isn't
easy to maintain. While some evolutionary forces encourage it, others
threaten the family values that are at its core."

"Songbirds are unusually
monogamous," the narrator continues. "But even as they
pair off and set up nests, inevitably some of them are lusting after
their neighbors." Cornell University behavioral ecologist Stephen
T. Emlen explains how a female songbird returning from migration
sometimes has to settle for "a fairly low-quality male"
in comparison with her neighbors. The female is now torn, according
to Emlen, between a desire to have a faithful mate who will help
her raise her young, and a desire to have her chicks sired by a
male of higher genetic quality. "Cheating, at least for certain
female songbirds," says the narrator, "gives their chicks
better genes, and therefore a better chance of surviving until they
can reproduce."

For a species of bird
in Panama, the narrator tells us, "survival of chicks is so
uncertain it's led to an amazing gender role reversal." So
many chicks are lost to crocodiles that females leave their eggs
for the males to raise, and go off to reproduce again. "Now
it's the females who care more about quantity than quality. Now
it's the females who fight over mates. Over time, they've taken
on traditionally male characteristics." Emlen explains that
the females of this species are aggressively territorial, and try
to attract "harems" of four or five males.

The narrator continues:
"So here is an evolutionary revelation about gender: Male and
female roles are not set in stone. They're largely determined by
which sex competes for mates, and which invests in the young."

Wait a minute! Just a
few scenes earlier, we were told that males and females behave as
they do because the former have lots of small, fast sperm and the
latter have a few large, complex eggs. Now we are told that the
behavior of males and females depends on which sex competes for
mates and which invests in the young. Yet the males of these Panamanian
birds still produce sperm, and the females still lay eggs. Apparently,
the reasons for male and female behavior are not as simple as Evolution
would like us to think.

D. Chimpanzees and
Bonobos

"Solving the problem
of passing on genes can even trigger the emergence of new species,"
the narrator says. "Sometimes what separates species is more
social than physical, as it is with our closest relatives, chimpanzees
and bonobos." Chimpanzees and bonobos look alike, live in similar
environments, and eat similar food. Chimpanzees are very pugnacious,
however, while bonobos are essentially peaceful. "Bonobos are
predisposed to make love, not war," the narrator tells us,
while two of them copulate on screen.

We watch wild chimpanzees
fighting--and occasionally stopping just long enough to have sex.
Then we visit the San Diego Wild Animal Park, where we witness bonobos
having heterosexual and homosexual intercourse "in every way
imaginable"--with a running commentary to make sure we don't
miss anything. No doubt many of the teenagers who watch the Evolution
series in their public school science classrooms will be hugely
entertained by these promiscuous primates.

So why do chimpanzees
make war, and occasionally love, while bonobos seem to make only
love? The answer, we are told, is female solidarity: Bonobo females
are "able to form alliances with each other and cooperatively
dominate males. And this changes the whole balance of power and
the whole social dynamic in the group, and makes it radically different
from chimpanzees."

Why have bonobos evolved
this strategy, and chimpanzees haven't? "It looks as though
a relatively simple change in the feeding ecology is responsible
for this dramatic difference in sexual behavior," we are told.
Bonobos live in forests where they can forage for food on the ground.
Although there are chimpanzees that live in similar forests, those
forests are also occupied by gorillas. The gorillas eat the food
on the ground, leaving the chimpanzees dependent on fruit trees.
So female chimpanzees have to forage intermittently and alone, without
the opportunities for social interactions enjoyed by female bonobos.

The narrator concludes:
"The simple fact that there was food available on the ground
appears to have been the force that drove the evolution of bonobos."
He speculates that some chimpanzees evolved into bonobos about two
million years ago because they were able to forage on the ground
after a drought killed the gorillas. We are told that if our own
ancestors had experienced the same conditions that supposedly led
to the evolution of bonobos, "we might have evolved to be a
totally different, more peaceful, less violent, more sexual species."

But does "more sexual"
really mean "less violent"? Violent chimpanzees seem to
be just as sexual as peaceful bonobos. The slogan "make love,
not war" sounds good, but sex and love are not synonymous--a
lesson which many people have learned only after deep personal tragedies.
What is Evolution trying to teach students here?

In any case, this account
of the evolutionary origin of bonobos is another just-so story.
We have two species with differing behavior patterns. But did differences
in behavior lead to the origin of two species? Or did the two species
originate in some other manner, with different behavior patterns
from the start? Did opportunities for ground foraging produce female
solidarity, which in turn established social peace? Or was it the
other way around? How can we know? Where's the evidence?

As we watch actors in
hairy costumes cross an African plain, the narrator acknowledges
that this theory of the origin of bonobos "is little more than
interesting speculation. But the idea behind it is consistent with
a growing but controversial body of scientific thought that claims
much of present-day human behavior is rooted in our distant past."
That controversial body of thought is "evolutionary psychology,"
and it claims that modern human behavior patterns were formed under
primitive conditions on the plains of Africa millions of years ago.

E. Evolutionary Psychology

"Evolutionary psychologists
begin by pointing out," says the narrator, "that regardless
of the culture in which we grow up, we all tend to respond the same
way to a surprising variety of things. Most of us find spiders unpleasant,
certain body types sexy, and particular smells disgusting. All,
they say, are legacies of our evolutionary past."

Researchers conduct an
experiment in which young men sleep in the same T-shirts night after
night, and put the shirts in plastic bags during the day. Then a
panel of young women smells the shirts and rates their sex appeal.
According to the researchers, the women consistently prefer the
shirts from those men who differ most from them in their immune
genes. "From an evolutionary perspective, this makes sense,"
the narrator tells us. "Choosing a mate with different immune
genes gives offspring a greater protection against viruses, parasites,
and other pathogens."

Facial beauty, we are
told, is simply a collection of subconscious biological cues that
let us know whether a potential mate is genetically desirable. In
one experiment women choose attractive male faces from a computer
program, and they tend to prefer more masculine faces at those times
of the month when they would most likely become pregnant.

Experiments such as these
are conducted by evolutionary psychologists who think human behavior
must be explained within a Darwinian framework. But of all the claims
by evolutionary psychologists, the narrator tells us, none are more
sweeping than those made by Geoffrey Miller: "He believes the
human brain, like the peacock's magnificent tail, is an extravagance
that evolved--at least in part--to help us attract a mate, and pass
on genes."

"The human brain,"
Miller says, "is the most complex system in the known universe.
It's wildly in excess of what it seems like we would need to survive
on the plains of Africa. In fact, the human brain seems so excessive
that a lot of people who believe in evolution applied to plants
and animals have real trouble imagining how natural selection produced
the human brain."

We watch ants scurrying
along a log as Miller continues: "All the other species on
the planet seem to get by with relatively small, simple nervous
systems that seem tightly optimized just to do what the species
needs to do to get by." The scene shifts to a yet another hunched-over
actor in a hairy costume. "I think people are perfectly sensible
in being skeptical about the ability of selection for survival to
account for the human brain. I think there was a sort of guidance
happening, there was a sort of decision-making process that was
selecting our brains. But it wasn't God, it was our ancestors. They
were choosing their sexual partners for their brains, for their
behavior, during courtship." We see an apeman-like figure squatting
on a narrow ledge. "And I think our semi-intelligent ancestors
were the guiding force, they were the guiding hand, in human evolution."

We return to the husband
and wife with their adopted child. "When choosing a mate, we
still notice beauty," the narrator says, "but what really
counts is how someone thinks, feels and acts. All of these are products
of the brain." After watching an old film clip of long-nosed
Cyrano de Bergerac professing his love to Roxanne, we are told:
"It's brains, not beauty, that win her heart."

Miller continues: "There
are all sorts of things that mess up brains. And paradoxically,
for that reason, brains make really good indicators of how fit you
are during courtship. In fact, they're probably better indicators
of that even than, than a peacock's tail is about how fit a peacock
is."

But Darwin formulated
his theory of sexual selection to explain the striking
differences we see between the males and females of some species.
Sexual selection is supposed to explain why male peacocks have large,
colorful tails--and females don't. But men's brains are not significantly
larger or more colorful than women's brains. Miller is quite right
when he says it is implausible to attribute the human brain to natural
selection, because our brain is so much more than what creatures
would have needed to survive on the plains of prehistoric Africa.
But attributing the human brain to sexual selection is even more
implausible

Nevertheless, we are
told that Miller's hypothesis is "an intriguing idea,"
because "it's not the same old saw of tool use, language, culture--it's
something entirely different." This is consistent with Stephen
Jay Gould's claim, quoted above, that "virtuosity in invention"
is "the criterion for acceptance" among evolutionary psychologists.
Evolution is telling us just-so stories.

The scene shifts to a
performance of the "Hallelujah Chorus" from Handel's Messiah,
as the narrator says: "Miller is just getting started when
he argues that the size of our brains can be attributed to our ancestors'
sexual choices. He's also convinced that artistic expression, no
matter how sublime, has its roots in our desire to impress the opposite
sex. And that includes music, art, the poetic and storytelling uses
of language--even a good sense of humor. According to Miller, they
all stem from our instincts for sexual display."

"I think,"
says Miller, "when a lot of people produce cultural displays,
what they're doing in a sense is exercising these, these sexual
instincts for impressing the opposite sex. They're not doing it
consciously, but what they're doing is investing their products
with an awful lot of information about themselves." We watch
part of a ballet, and Miller concludes: "I think the capacity
for artistic creativity is there because our ancestors valued it
when they were making their sexual choices."

So Miller sees all of
human culture as a by-product of sexual urges--just as Freudian
psychology did. But Freudian psychology is no longer considered
good science. "Freud's views lost credibility," wrote
University of Chicago evolutionary biologist Jerry A. Coyne in 2000,
"when people realized that they were not at all based on science,
but were really an ideological edifice, a myth about human life,
that was utterly resistant to scientific refutation. By judicious
manipulation, every possible observation of human behavior could
be (and was) fitted into the Freudian framework. The same trick
is now being perpetrated by the evolutionary psychologists. They,
too, deal in their own dogmas, and not in propositions of science."

Although this episode
acknowledges that Miller's ideas are controversial, it presents
them uncritically, without mentioning the fact that many biologists
don't even consider them scientific. Like the controversy over the
biological reasons for sexual reproduction, the controversy over
the scientific status of evolutionary psychology is completely ignored
by Evolution.

This shallow and lopsided
account of evolutionary psychology also has a religious--or rather
anti-religious--component. Despite the lack of evidence for his
hypothesis, Miller says he is confident that the reason we have
our brains "wasn't God, it was our ancestors. They were choosing
their sexual partners for their brains, for their behavior, during
courtship." And to illustrate Miller's claim that artistic
creativity is reducible to our ancestors' sexual choices, Evolution
chooses--of all things!--the "Hallelujah Chorus."

God and the Messiah.
More religion. Despite the assurance by Evolution's producers that
they would avoid "the religious realm," they can't seem
to stay away from it.

F. Into the Future?

As we watch a collage
of scenes from throughout the episode, the narrator reminds us:
"Sex is at the heart of evolution. The process of mixing and
passing on genes produces variation, that helps species meet the
challenge of life in a competitive world. Sexually selected variations
are those that help individuals find mates, and successfully raise
young. That's how, for humans, sex became fun, and parenting rewarding."

The scene shifts once
more to actors wearing apeman costumes, and the narrator continues:
"Those of our ancestors who took pleasure from sex, and satisfaction
from parenting, had more surviving offspring than those who didn't.
That was true generation after generation. These traits are now
almost universal. Even if we choose not to have children, we still
enjoy sex. And even when we adopt a child who doesn't carry our
genes, we can still find parenting rewarding."

We look in once again
on the husband and wife who adopted a baby. Humans, we are told,
are the only species that will care for biologically unrelated children
over the long term. "Humans are unique," the narrator
says. "We are a product of evolution. But we've taken the first
tentative steps towards controlling our evolutionary destiny. It's
a brave new world we're entering. Only time will tell if we'll be
as successful at guiding our future as evolution has been."

So parenting is a good
thing--even when it is no longer connected to sex, when it no longer
serves the evolutionary purpose of passing on genes. This episode
leaves us with some strangely mixed messages. The reproductive behavior
of males and females is due to the differences between sperm and
eggs--except in certain Panamanian birds, when it isn't. Sexual
selection produces striking differences between males and females--except
in the evolution of the human brain, when it doesn't. And parenting
must be understood in an evolutionary perspective--except in human
families with adopted children, when it mustn't.

So this episode completely
ignores three major controversies raging beneath the surface of
its topic: one over the biological reasons for sex, another over
the scientific status of evolutionary psychology, and still another
over the mystery of altruism. Rather than educate viewers about
what's really going on in biology, Evolution emphasizes two simple-minded
messages: God is out, and sex is in. Sex is more important than
life itself. Sex is our immortality. Sex is why we have big brains.
Instead of providing us with solid scientific evidence, or an honest
treatment of serious scientific controversies, this episode relies
on just-so stories and sex scenes.

Why Sex? It's a fascinating
question. But viewers of Evolution may find themselves asking: Why
so much sex--and so little science?

Notes

.
For a review of the research on Mexican minnows, see Robert C.
Vrijenhoek, "Animal Clones and Diversity," BioScience
(August, 1998), at:

The 1988
study that reported no consensus on solving the problem of sex
also reported: "A survey of evolutionary biologists would
doubtless come up with a consensus that the elucidation of the
selective pressures responsible for the origin and maintenance
of sex is a `big' (maybe the `biggest') unsolved problem in evolutionary
biology." Richard E. Michod and Bruce R. Levin, The Evolution
of Sex: An Examination of Current Ideas (Sunderland, MA: Sinauer
Associates, 1988), vii.

The quotations
from the 1998 special issue of Science are from Bernice Wuethrich,
"Why Sex? Putting Theory to the Test," Science 281 (1998),
1980-1982. The same issue included the following articles of interest:
Pamela Hines & Elizabeth Culotta, "The Evolution of Sex,"
Science 281 (1998), 1979; N. H. Barton & B. Charlesworth,
"Why Sex and Recombination?" Science 281 (1998), 1986-1990.

For more
about the controversy, see: Lynn Margulis and Dorion Sagan, What
Is Sex? (New York: Simon & Schuster, 1997)--see especially
121: "The Red Queen idea [which forms the basis of Vrijenhoek's
hypothesis] is simply a cute name for a zoological myth";
and John Cartwright, Evolution and Human Behavior (London: Macmillan,
2000), especially 90-101.

.
The Stephen Jay Gould quotation is from "Sociobiology:
the art of storytelling," New Scientist (November 16, 1978),
530.

.
The Coyne quotation is from Jerry A. Coyne, "Of Vice and
Men: The fairy tales of evolutionary psychology," a review
of Randy Thornhill and Craig Palmer's A Natural History of Rape,
in The New Republic (April 3, 2000), last page. The entire review
is available at:

http://www.thenewrepublic.com/040300/coyne040300.html

For a recent
critique of sociobiology and evolutionary psychology for non-specialists,
see Tom Bethell, "Against Sociobiology," First Things
(January, 2001)

http://print.firstthings.com/ftissues/ft0101/articles/bethell.html

The Birkhead
quotation is from Tim Birkhead, "Strictly for the birds,"
a review of Geoffrey Miller's book, The Mating Mind in New Scientist
(May 13, 2000), 48-49; the Tattersall quotation is from Ian Tattersall,
"Whatever turns you on," a review of Geoffrey Miller's
book, The Mating Mind, in The New York Times Book Review (June
11, 2000).

This problem
with just-so story telling is not some minor irritation. . . .
The problem runs much deeper and wider, embracing many new disciplines
of evolutionary psychology, Darwinian medicine, linguistics, biological
ethics and sociobiology. Here quite vulgar explanations are offered,
based on the crudest applications of selection theory, of why
we humans are the way we are. . . . There seems to be no aspect
of our psychological make-up that does not receive its supposed
evolutionary explanation from the sorts of things our selfish
genes forced us to do 200,000 to 500,000 years ago. . . . Not
only is there the embarrassing spectacle of psychologists, philosophers
and linguists rushing down the road of selfish genetic determinism,
but we are also shackled with their self-imposed justification
in giving `scientific' respectability to complex behavioral phenomena
in humans which we simply do not so far have the scientific tools
and methodologies to investigate.

.
The E.O. Wilson quotation is from Sociobiology (Cambridge, MA:
Harvard University Press, 1975), 382. The definition of altruism
is taken from the abridged paperback edition (1980), 55.

For more
about the challenge that altruism poses for evolutionary theory,
see H. R. Holcomb, Sociobiology, Sex, and Science (Albany, NY:
State University of New York Press, 1993); K. R. Monroe, The Heart
Of Altruism: Perceptions Of A Common Humanity (Princeton: Princeton
University Press, 1996); and H. Plotkin, Evolution in Mind: An
Introduction to Evolutionary Psychology (Cambridge, MA: Harvard
University Press, 1997).